自制了一种用于等离子体质谱的可拆卸式的直接注人高效雾化器,它由雾化器体、拉尖毛细管(外径0.37mm,内径0.25mm,尖端的内外径分别为30和40岬1)、空心不锈钢管(内外径分别为O.5和2.0mm)和雾化器适配器用环氧树脂胶组装而成,拉尖毛细管由商品石英毛细管采用火焰加热两步拉制法制作。将雾化器浸入沸水中,软化环氧树脂胶,从而实现雾化器各组件的拆卸分离及破损或堵塞的进样毛细管的更换。自制雾化器在雾化气流量为027L/rain,样品提升量在50μL/min,发射功率为1500W达到最佳灵敏度。自制的直接注入高效雾化器的灵敏度、检出限和精密度优于MicroMist雾化器,但后者的多原子离子水平低于前者。自制的直接注入高效雾化器结合微流动注射已用于微量血清中铂的分析,也用作芯片电泳和等离子体质谱的串联接口实现了碘的形态分析。自制的直接注入高效雾化器的制作成本约为商品雾化器的1%,且损坏或堵塞的进样毛细管更换十分方便。
We developed a low-cost, demountable direct injection high-efficiency nebulizer (DIHEN) for inductively coupled plasma mass spectrometry (ICP-MS). It consisted of an enlarged microconcentrie nebulizer based body, a tapered capillary (0.25 mmi. d. and 0.37 mm o. d. , 30 μm i.d. and 40 μm o. d.at the tip), a hollow stainless steel tubing (0.5 mm i. d. and 2.0 mm o. d. ) and two adapters made from polytetrafluoroethylene (PTFE), which were assembled by epoxy resin. The tapered capillary was reproducibly fabricated according to a flame-heated two-step drawing method. After immerging into boiling water, the epoxy resin became soft and the components could be taken apart simply. Then the broken or blocked sample capillary was replaced by a new tapered capillary with the same dimensions and then they were assembled again. The optimal sensitivity was obtained when the gas flow rate was 0.27 L/min with a sample uptake rate of 50 ~L/min and a forward power of 1500 W. The sensitivities, detection limits and precisions of the homemade DIHEN under optimal operating conditions are similar, or better than those obtained with the MicroMist nebulizer, to some extent, though the polymeric ion levels of the former are higher than those of the latter. The utility of the homemade DIHEN for the analysis of small-volume samples was demonstrated by microscale flow injection analysis of Pt in serum samples. Then the homemade DIHEN was further utilized to couple microchip electrophoresis to ICP-MS for iodine speciation. The cost of the homebuilt DIHEN is about 1% price of the commercial Meinhard DIHEN, and the demountable construction permits that the blocked or broken sample capillary could be conveniently renewed with the same capillary in dimensions, obtaining low cost and easy maintenance.